Merge pull request #1689 from EliahKagan/312stable

No longer allow CI to select a prerelease for 3.12

Author: Byron

.github/workflows/pythonpackage.yml

@@ -17,9 +17,7 @@ jobs:
       matrix:
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
         include:
-          - experimental: false
-          - python-version: "3.12"
-            experimental: true
+        - experimental: false
 
     defaults:
       run: